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      /* background:linear-gradient(#fb3 30%,#58a 0);
      background-size: 100% 30px; */
      /* background:linear-gradient(#fb3 20%,#58a 80%); */
      /* background:linear-gradient(#fb3 40%,#58a 60%); */
      /* 橙蓝一半 */
      /* background:linear-gradient(#fb3 50%,#58a 50%); */
      /* 橙色覆盖蓝色 */
      /* background:linear-gradient(#fb3 100%,#58a 100%); */
      background:linear-gradient(#fb3 40%,#58a 30%);
      /* 渐变的起止色分别是第一个和最后一个指定的值 */
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